TwoStepBicubicZoom.scala

val in0   = ImageFileIn("in")
val wIn   = in0.width
val hIn   = in0.height
val wOut  = "width".attr(1920)
val hOut  = "height".attr(1080)
val num   = "num-frames".attr(100)
val gamma = "gamma".attr(1.0)
val szIn  = wIn  * hIn
val szOut = wOut * hOut
val in    = RepeatWindow(in0, szIn, num)
val zoomEnd = (wOut / wIn) min (hOut / hIn)
val idxOut = ArithmSeq(start = 1, length = num)
//val sx    = Line(1.0, zoomEnd, length = num)
val sx    = idxOut.linExp(1, num, 1.0, zoomEnd)
//val sx    = Line(zoomEnd, zoomEnd, length = num)
val sy    = sx
//val sxW   = RepeatWindow(sx, 1, szOut)
//val syW   = RepeatWindow(sy, 1, szOut)
//val txW   = RepeatWindow(tx, 1, szOut)
//val tyW   = RepeatWindow(ty, 1, szOut)
//sxW.poll(Metro(szOut), "sx")
//syW.poll(Metro(szOut), "sy")
//txW.poll(Metro(szOut), "tx")
//tyW.poll(Metro(szOut), "ty")

wIn.poll(0, "width-in")
hIn.poll(0, "height-in")
zoomEnd.poll(0, "zoom-end")

val sx1 = sx.sqrt
val sy1 = sy.sqrt
val sx2 = sx1
val sy2 = sy1

val wFull1 = wIn * sx1
val hFull1 = hIn * sy1
val tx1   = 0.0 // (wIn - wFull1) * 0.5
val ty1   = 0.0 // (hIn - hFull1) * 0.5

val wFull2 = wFull1 * sx2
val hFull2 = hFull1 * sy2

val tx2   = (wOut - wFull2) * 0.5
val ty2   = (hOut - hFull2) * 0.5

val sxW1  = RepeatWindow(sx1, 1, szIn)
val syW1  = RepeatWindow(sy1, 1, szIn)
val txW1  = RepeatWindow(tx1, 1, szIn)
val tyW1  = RepeatWindow(ty1, 1, szIn)

val sxW2  = RepeatWindow(sx2, 1, szOut)
val syW2  = RepeatWindow(sy2, 1, szOut)
val txW2  = RepeatWindow(tx2, 1, szOut)
val tyW2  = RepeatWindow(ty2, 1, szOut)

val zoom1 =
  AffineTransform2D(in,
    widthIn = wIn, heightIn = hIn, widthOut = wIn, heightOut = hIn, 
    m00 = sxW1, m11 = syW1, m02 = txW1, m12 = tyW1, m01 = 0.0, m10 = 0.0,
    zeroCrossings = 0, wrap = 0
  )

val zoom = AffineTransform2D(zoom1,
  widthIn = wIn, heightIn = hIn, widthOut = wOut, heightOut = hOut, 
  m00 = sxW2, m11 = syW2, m02 = txW2, m12 = tyW2, m01 = 0.0, m10 = 0.0,
  zeroCrossings = 0, wrap = 0
)

val adj = If (gamma sig_== 1.0) Then { 
  zoom
} Else {
  zoom.pow(gamma.reciprocal)
}
val out = adj.clip(0.0, 1.0)
ImageFileSeqOut("out", out, width = wOut, height = hOut,
  quality = 95, indices = idxOut)